1. Field of the Invention
The present invention relates to an ink set and an image forming method.
2. Description of the Related Art
A recording method using an ink jet method is widely used in terms that it may record a high quality image on a wide variety of recording media by discharging ink in a droplet form from a number of nozzle holes provided in an ink jet head.
In an image recording using the ink jet method, an image recording method may be used in which an image is formed by contacting a pigment ink with a process liquid which aggregates ingredients in the pigment ink. A combination of the pigment ink and the process liquid such as this is referred to as an ink set.
For example, as an image recording method that may suppress the curl of a recording medium, the image recording method in which the pigment ink and the process liquid containing a polybasic acid having greater than or equal to two carboxyl groups or hydroxyl groups within the molecule is used as a combination is known (for example, see JP2008-126413A).
Also, as an ink set which may form a uniform image where dot diameters are identical, the ink set including the pigment ink and the process liquid having at least one of a polyvalent organic acid, polyphosphoric acid, and metaphosphoric acid (the process liquid) is known (for example, see JP2010-188661A).
Also, as an ink set which may improve bleeding or a show through, the ink set including a combination of the pigment ink and the process liquid having a polyvalent metal salt, tricarballylic acids and a liquid medium (a process liquid) is known (for example, see JP2008-265122A).
Also, as an ink jet recording method in which a picture quality of the image is outstanding, the ink jet recording method including a process liquid applying step for applying process liquid containing an aggregating agent which aggregates ingredients in the ink composition (for example, an organic carboxylic acid having greater than or equal to divalence) on the recording medium before discharging the ink composition which forms an ink image, and an image recording step for recording the image using the ink composition of at least two types of ink with different surface tension is known (for example, see JP2010-46945A).
Also, as an ink set which has an excellent ink aggregating property and may record an image with superior scratch resistance and picture quality at high speed, the ink set including the ink composition containing a pigment, resin particles, and a polymerizable compound, the aggregating agent which aggregates ingredients in the ink composition (for example, an organic acid having greater than or equal to divalence), and the process liquid containing the polymerizable compound is known (for example, see JP2010-69805A).